The Violet Slate / Purple Grey Theory

When the telephone system was designed, it was very much a point to point communications network. Each endpoint (telephone) had a unique identifier (phone number) and was connected back to the central office via a dedicated twisted-pair of wires. To keep the circuits separated and identifiable for troubleshooting, the Bell System needed a method that would be simple, easy to remember and expandable to service hundreds of thousands of customers. But, how could this possibly be done? Certainly, there were not enough colors in the spectrum to support this!

But the Bell System came to the rescue, born of innovation and engineering standards. They devised a way of using just 10 different colors in a unique combination, and likely had a 50-page document on why. In any case, they defined the colors into 2 groups.

Major Colors               Minor Colors

White                          Blue
Red                              Orange
Black                           Green
Yellow                         Brown
Violet                          Slate

The last 2 were Violet and Slate, and the ‘reason’ didn’t matter. It was just the way it was, and as apprentice learned from their mentor, these colors were passed down, generation to generation of telephone men. It was how I learned, it was how my partner who taught me learned, and it was how his mentor taught him. It was the ‘Bell Way’ and that is all we needed to know.

Fast forward in my career from ‘punch-jockey’ to PBX installer, to Systems Engineer and Technician, to Telecom Manager that was currently interviewing candidates for a position. I wanted someone that had been around. Someone that grew up with some of the old ‘Bell value standards’.

One of my questions on an interview was “What color is the 25th pair?” I quickly realized, the candidates that had been around, used the familiar Violet/Slate colors, and the greener candidates would name the pair as “Purple/Grey”. Upon questioning them, they knew Violet-Slate but were taught, Purple-Grey. Despite their ‘age’ or ‘experience in the industry’, it became quite clear that there were 2 distinct groups of candidates out there. The well-seasoned Violet Slate technicians, that would maintain a meticulous wire frame, used the right tools for the right job, and did things the ‘old-school way’.

These were the guys I wanted to do cabling, nd managing the wire plant, and building the physical side of my switch room. The Purple Greys were the other guys, newer to the industry, and innovative in their thinking. They all had laptops, were already on the internet, and used software tools like Excel.

Immediately, age didn’t matter. Their experience didn’t matter. I stumbled upon the ultimate litmus test to instantly define the right person for the right job based on experience! What a great find! From that day forward, everyone became a Violet Slate guy, like myself, and the good Purple Gray guys, like Matt Konwiser, recognized their doppelganger,  and more importantly the value of both of them teaching each other.

And so concludes the story and theory of Purple Grays and Violate Slates.  Which one are you?

There is no wrong answer.